Airbag device comprises an inflator which is a gas-generating device, and an airbag. The airbag deploys due to the gas generated by the inflator, protecting passengers from impact during a collision.
As shown in FIG. 7, an inflator 1 typically includes a pressure container 2 having a diffuser 2a and a shallow dish base 2b in the pressure container 2, and an ignition means 3 operating due to an electrical signal generated after a collision is detected and gas generant 4 ignited by the ignition means 3 are housed. The ignition means 3 is composed of an initiator 3a and ignition enhancer 3b. 
At the time of collision, the gas generant 4 burns, and instantaneously harmless gas is generated. The generated gas passes through a filter 5 and is finally discharged from gas exits 2aa. In order to burn the gas generant 4 safely and stably, a diffuser 2a, shown separately in FIG. 7 (a) in a state prior to welding, is welded to the base 2b, as shown in FIG. 7 (b), so that the gas generant 4 is enclosed.
Patent Reference 1: Japanese Laid-Open Patent Application No. H11-334517